To check the condition of the hardware on the computer needs to be diagnosed. On the computer recognized three types of diagnostics, namely:
* POST (Power-On Self-Test)
* Common diagnosis (routine)
* Diagnose and solve seek damages
1. POST Steps
Every time the computer is turned on automatically will start with the step known as POST diagnostics. POST will examine and test all system components. If a problem occurs during POST, a message will be delivered to the user. Such messages can be: a message on-screen display, beep sound, or both. Indications of a problem during POST stated:
* Error code: two to five digit number
* Error messages: a short message in English (there are some
message indicating the problem)
* Code beep: beep sound sequence
With a very varied and motherboard manufacturers, the ROM BIOS beep codes also vary given the same meaning for the damage will be given a different beep codes that because of differences of the manufacturer or the motherboard ROM BIOS. Tests all memory including the steps of this POST. The duration of the test depends on the size of memory installed capacity. However, the POST does not check all the extra equipment / expansion, such as: printers, modems, etc..
The POST steps are as follows:
1. CPU test: interruptions closed, testing the internal flags, and testing of internal registers
2. Test BIOS ROM checksum: BIOS ROM checksum test. Results checksum LSB must be zero.
3. Test Timer 1: Timer 1 8253 programmable in operating mode 2, checking on the basis of access counters, check in counter.
4. DMAC test: testing on all channels register addresses and register counter DMA, channel 0 DMA initialization, initialize timer 1, starting memory refresh cycle.
5. 16 KB DRAM test: testing on 5 different pattern Aah, 55H, FFH, 01h, 00H write and read back.
6. Initialization Interrupt controller: control word sent to the initialization mode interrupsi, setting an interrupt vector in memory.
7. Test Interrupt controller: setting and interrupt reset register, placing the stack-stack error interrupt.
8. Initialization Timer 0: timer 0 is initialized in operation mode 3, check the timer 0.
9. CRT test controller: initialize CRT controller, video RAM test, check some parity error, setup video mode through the reading of konfigura-si, timing and signal synchronization testing images.
10. 16KB DRAM test above: the test on 5 different pattern Aah, 55H, FFH, 01h, 00H write and read again, if there is an error will displayed the error address and data on the screen.
11. Keyboard test: check your keyboard with a keyboard reset condition, a check of keystrokes on the keyboard.
12. Disk Test drive: check all floppy adapter card and disk drive that is attached, POST call the operating system from disk.
POST steps above can be summarized as follows:
1. Test 1 (Basic System): check the power supply, MPU, bus, and ROM (step ab)
2. Test 2 (Extended Systems): check the system timers, DMAC, DRAM 16KB initial location and PIC (step ch)
3. Test 3 (Display): check control system monitors the video signal on the card and VRAM (step i)
4. Test 4 (Memory): check the location of DRAM on top of 16KB with a sampling / sampled (step j)
5. Test 5 (Keyboard): check the keyboard (step k) f) Test 6 (Drive): check the adapter cards and disk drives and peripherals
hard disk (step l)
2. Error Message During POST
1. Test 1 (Basic System Error), the system stops with no display and beep sound, even though the cursor may appear.
2. Test 2 (Extended System Error), one long beep sound followed by a short beep sound, and POST execution stopped.
3. Test 3 (Display Error), one long beep followed by two short beeps sound, and POST continues with the next test.
4. Test 4 (Memory Error), there is the display number that indicates the error code.
5. Test 5 (Keyboard Error), there is the display number that indicates the error code.
6. Test 6 (Drive Error), no display number 601, 1780, or 1781 that shows an error code.
To locate or determine the type of damage is PC needed examination of the condition of the hardware on the computer. This examination includes: POST (Power-On Self-Test), general diagnosis (routine), and diagnostics to find and resolve the damage. From the results of this examination will be known location of the damage and the type of damaged components and then carried out repairs to the part that suffered the damage.
1. Troubleshooting Motherboard
a). Problems that may occur
Computer system consists of the motherboard, daughter board, power supply, floppy drives, monitors, keyboards, and some equipment connected via the connector and cable. Problems in the equipment will affect the operation of other equipment and sometimes interfere with the operating system. Checking below will help solve the problem.
* Check the cable connection is the main power supply and DC voltage cables.
* Check the keyboard cable connection.
* Check the monitor cable connection and the monitor power cable.
* Check CMOS configuration setting